I will match up Matthew 16:27-28 (and parallel) with the Olivet Discourse.

Matthew 16

[27] For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
[28] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.

Matthew 24

[30] And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.

Matthew 16

[27] For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
[28] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.

Matthew 24

[30] And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.

Matthew 16

[27] For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
[28] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.

Matthew 24

[31] And he shall send his angels with a great sound of a trumpet...

Matthew 16

[27] For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
[28] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.

Matthew 24

[34] Verily I say unto you, This generation shall not pass, till all these things be fulfilled.

Timing is stated emphatically.

Matthew 16

[27] For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
[28] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.

Matthew 24

[34] Verily I say unto you, This generation shall not pass, till all these things be fulfilled.

An equivalent prediction is given on the timing. There are different interpretations of Matthew 24:34, but on a "this first century generation" interpretation it fits perfectly with Matthew 16:28. There is a harmony between them.

Mark 9

And he said unto them, Verily I say unto you, That there be some of them that stand here, which shall not taste of death, till they have seen the kingdom of God come with power.

Matthew 24

[30] And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.

Luke 9

[26] For whosoever shall be ashamed of me and of my words, of him shall the Son of man be ashamed, when he shall come in his own glory, and in his Father's, and of the holy angels.
[27] But I tell you of a truth, there be some standing here, which shall not taste of death, till they see the kingdom of God.

Luke 21

[31] So likewise ye, when ye see these things come to pass, know ye that the kingdom of God is nigh at hand.

Matthew 16

[27] For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works.
[28] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.

Matthew 25

[31] When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory:
[32] And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats...

Everything in those two verses (Matthew 16:27-28) can be matched up well with the Olivet Discourse.

Try matching up that material with the transfiguration. Try matching up that material with pentecost. (Or whatever other interpretation Christians will come up with.)

Some will say that verse 27 speaks of the "2nd coming", but that verse 28 speaks of something distinct.

If verse 27 is about the 2nd coming, and everything in verse 28 also fits with the 2nd coming/Olivet Discourse, then there is no good reason to say it has suddenly switched subject!

I think you're right and no one reading those lines would see anything else unless they had an ulterior motive. It seems that one of the themes of gJohn is that we shouldn't be on the look out for a second coming because Jesus ascended and returned shortly after his resurrection and then handed his mantle to Peter (influence of gLuke on gJohn).

You may find it useful postulating (without over-committing yourself) to the sequence of the gospel apocalypse(s). This will help you to gauge how Mark, Matthew and Luke constructed the discourse. Analyzing Matthew without having a picture of his sourcing might not give you a good enouyh picture of the intent or intents of the passage.

For example, Mark uses an uncanny saying in 13:20 " And if the Lord had not shortened the days, no human being would be saved; but for the sake of the elect, whom he chose, he shortened the days". Matthew "corrects" this and places the shortening of the days into the future, with the rest of the prophecy: "And if those days had not been shortened, no human being would be saved; but for the sake of the elect those days will be shortened." (24:22) The tenses may seem like an inconsequential matter, and the more literalist among interpreters would not see big difference between what Jesus says in the two gospels, ascribing Mark's abuse of the past perfect as an example of his barbaric Greek. But the problem comes when one analyzes the statement itself : "what does the shortening of the days relate to ?" IAICT this is not something that can be traced to an OT textual paraphrasing. (At least, I haven't found a parallel). This may be an allusion to something "the elect" are experiencing (Mk 4:11, Mt 13:11), while the rest of the sinners are not. I have come to believe that without actually understanding what it is, the passage will remain obscure.

FWIW, my understanding is that Mark deliberately "faked" Jesus prophesying future events (some of which alluded to the 66-73 war ex eventu) in order to assert the gnosis of the mystery by the elect. Jesus in Mark 9:1 saying "Truly, I say to you, there are some standing here who will not taste death before they see that the kingdom of God has come with power" does not speak of historical events but of the "peak" experience of the Jesus epiphany. Matthew 16:28 does the same thing of course, but Matthew removes the "clue" of the shortened days.